Characterizing Populations and Reproduction Strategies

Question 1

Population

Answer 1

All members of a single species living in a specific area at the same time

Question 1

population size

Answer 1

Number of individuals

Question 2

Population Density

Answer 2

Number of individuals living in a given area (Individuals/area^2)

Random, Uniform, Clustered

Question 3

Birthrate or natality

Answer 3

Number of live births added annually per 1000 individuals

Crude Birth Rate = (No. of live births in a year/Population size) x 1000

Question 4

Deathrate or mortality

Answer 4

Number of deaths added annually per 1000 individuals

Crude Death Rate = (No. of deaths in a year/Population size) x 1000

Question 5

natural Growth rate

Answer 5

(%) = Birthrate - Deathrate

Question 6

Doubling time

Answer 6

(Years) = 70/Growth rate (%)

Question 7

Immigration

Answer 7

Movement of individuals into a population

Question 8

Emigration

Answer 8

Movement of individuals out of a population

Question 9

Total growth rate (%)

Answer 9

Total growth rate (%) = (crude Birthrate + immigration) - (crude death rate + emigration)

Question 10

Calculating population size using growth rate

Answer 10

P(t) = P(0)e^rt

P(t) = Population at the time t
P(0) = initial population at time 0
e = eulers number
r = growth rate
t = length of time

Question 11

Sex ratio

Answer 11

Number of males with respect to number of females

Number of males/number of females = Sex Ratio

Question 12

Age distribution

Answer 12

1. Pre-reproductive juveniles
2. Reproductive adults
3. Post-reproductive adults

Question 13

Types of growth

Answer 13

Exponential (J-curve)

Logistic (S-curve)

Question 14

Exponential Growth Rate

Answer 14

An increase in individuals per unit of time “Growth with no limit”

dN/dt = rN

N = number of individuals
r = rate of growth

Question 15

Carrying Capacity

Answer 15

The maximum population size of a biological species that can be sustained by that specific environment

Question 16

Logistic Growth Rate

Answer 16

Changes in growth over time

Growth slows when approaching carrying capacity

dN/dt = rN((K - N)/K)

N = number of individuals
r = rate of growth
K = carrying capacity

Question 17

Limiting Factors

Answer 17

Factors that prevent the further increase of the population

Determine an ecosystem’s carrying capacity

Question 18

Environmental Resistance

Answer 18

The totality of all limiting factors

Question 19

Factors affecting growth

Answer 19

Density-dependent factors
1. External Factors
2. Internal Fators

Density-independent factors

Question 20

External Factors

Answer 20

habitat quality, food availability, interactions

Question 21

Internal Factors

Answer 21

Slow growth and maturity, body size, metabolism, hormonal status

Question 22

Density-dependent factors

Answer 22

Effect intensifies with increase in population size

Question 23

Density-independent population factors

Answer 23

Population affected no matter what size (often abiotic)

Such as climate extremes, seasonal cycles, pollutants in the environment, fires

Question 24

R-strategies

Answer 24

1. Usually small
2. Highly reproductive rate
3. High mortality
4. Ignored offspring

Depend on high rate of reproduction and growth (r)
- may overshoot carrying capacity and experience population crashes
- too many young, few will survive

Question 25

K-strategies

Answer 25

1. Tend to be large
2. Live long lives, mature slowly
3. Care for offspring
4. Low reproductive rate
5. Low mortality

Adapted for slower growth conditions near carrying capacity (K)